They drove into an underground entrance to the headquar-ters building.

The garage, with an underground entrance for school buses, would have a public plaza on its roof.

It was the underground entrance to a busy department store.

"We're just going to sneak in the underground entrance and flush them out."

We're going to try to enter through a hidden underground entrance.

"I need to wait here, just to make sure someone else doesn't try to sneak in through the underground entrance down there."

I believe there's a secret underground entrance from some other place on the grounds.

December 9, 1957: The north side underground entrance opens.

Perhaps there existed a secret underground entrance to the floor of the death pit.

He sat on the concrete edge of the underground entrance.